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To a human, the idea of getting your limbs tangled up doesn’t make much sense; not only do our arms and legs lack the flexibility needed for a sailor’s knot, they are also under near-total conscious control. The only parts of the human body that are largely beyond our control, things like the heart and intestinal muscles, have a limited range of motion and can’t cause trouble through much other than outright failure.

An octopus, however, has eight boneless legs that at least partially control themselves — an octopus leg severed from the body will still latch on to just about anything you put next to it, grabbing hold with the leg’s major muscles and with its battery of grasping suckers.

This situation seems to demand an explanation: how can a bundle of (at least) partially automatic grabbers keep from automatically grabbing each other? A team from Jerusalem’s Hebrew University thinks they’ve found the answer thanks to an innovative experiment exposing octopuses to their own severed limbs.

Now, that might sound horrifying, but remember that octopuses regularly lose legs in nature and display no signs of distress as they wait for the limb to regrow. The cephalopods do seem to recognize their own anatomy though, and have the experimentally helpful tendency to pick up and hold their own former limbs upon finding them.

Below, you can view a video of one of these animals picking up a severed leg — though it’s honestly a bit difficult to see exactly what’s going on.

A severed octopus leg will remain responsive for up to an hour after amputation, and the researchers exploited this fact to test the legs’ affinity for different objects when (obviously) the brain cannot consciously interfere. They found that an octopus leg will automatically grab hold of just about anything — except the body of its host, another octopus, or another severed leg. Importantly, the legs resumed their grabbing when presented with a skinned severed leg — though they claim to have been “surprised” by this result, I can’t think of any reason this team would have skinned an octopus leg without at least a hunch in that direction.

Regardless, the Israeli researchers present the first evidence of chemical control over the suckers and overall action of octopus legs. This is why octopuses do not get tangled: they are chemically restrained from doing so. Despite the fact that their legs almost always wave about with little oversight from the brain, the animal’s biochemistry stops it from self-hugging to death.

As evidenced by the fact that the experimentally handicapped octopuses can willingly pick up their old limbs, the animals can clearly choose to override the chemical signals when necessary. Even more interesting, they seem to recognize their own severed legs as different from those of a stranger; one particularly cannibalistic species chose to eat any severed limbs it found, save for its own.

It’s worth pointing out that recent research implies that octopuses actually do not have eight legs, but rather two legs supplemented by six arms. There’s little anatomical difference, but octopuses have been shown to rely on their rear-most pair of limbs for “walking” on the sea floor, keeping the front six free to manipulate their environment. Many even seem to have a favorite eating arm — third from the front, in most cases.

Next up for this team is identification of the particular chemicals that stop the grabbing action. Since they’ve already shown that this mystery compound is excreted from the skin, however, it shouldn’t take them terribly long to find. When they do, they’ll have a very early insight into the relationship between central and peripheral (conscious vs unconscious) limb control. This will be interesting to marine biologists and regular neurologists alike; how our similarly divided human nervous systems interact is also still largely unknown.

And don’t worry: by the time you read this, these septipuses will have had plenty of time to regrow and become octopuses once more.